M6-T03: add pricing profile framework + strategy registry

- app/integrations/pricing: profiles.py (pydantic ManualProfile/TibberProfile,
  load_profile/list_profiles/validate_values), manual.yaml + tibber.yaml
  (structure-only, no price values), strategies.py (register/get_strategy,
  manual dual-tariff + tibber strategies, all Decimal).
- tibber strategy matches nearest tibber_price with starts_at <= t0.
- tests for profiles + strategies (hand-checked dual-tariff & tibber math).

docs/design/m6-tibber-dynamic-energy.md

@@ -315,7 +315,7 @@ Phase D（API + 前端）
 - **Reviewer checklist**: secret 不回显/不进 OpenAPI 示例；`_settings_payload` 无遗漏；默认 off。
 
 ### M6-T03 — pricing profile 框架 + strategy 注册表
-- **Status**: `todo` · **Depends**: none
+- **Status**: `done` · **Depends**: none
 - **Context**: 仓库内 `manual.yaml`/`tibber.yaml` 定结构（pydantic 校验），加 price strategy 注册表（manual/tibber 出价）。纯模块，单测。
 - **Files**: `create app/integrations/pricing/__init__.py`、`pricing/profiles.py`（pydantic 模型 + `load_profile`/`list_profiles`/`validate_values`）、`pricing/profiles/manual.yaml`、`pricing/profiles/tibber.yaml`、`pricing/strategies.py`（`register_strategy`/`get_strategy`、`manual`/`tibber` 实现）；`create tests/test_pricing_profiles.py`、`tests/test_pricing_strategies.py`
 - **Steps**: